\subsubsection{Conclusion}
This project is a typically interdisciplinary project in which research was made on two fronts at the same time.
-On one side our Electrical engineering colleagues designed, simulated and implemented the device itself.
-On our side we evaluated the perception the haptic effect by users.
+On one side, our Electrical engineering colleagues designed, simulated, and implemented the device itself.
+On our side, we evaluated the perception of the haptic effect by users.
Both research benefitted to the other.
Our main contribution was the evaluation of variable friction parameters for the design of
an output vocabulary with programmable friction devices.
Then we worked on the syntactic level, and proposed definitions of tactile patterns and textures.
We compared the users' estimation of similarity of tactile patterns made of different shapes and densities implemented with a Stimtac device and with coated paper cards.
-We observed differences of grouping stragety acrross conditions, suggesting differences of perception between the haptic device and the paper cards.
-It means that results about perception made with research prototypes are hard to generalize, and that using physical props is an alternative to evaluate best-case scenarios.
+We observed differences of grouping strategy across conditions, suggesting differences of perception between the haptic device and the paper cards.
+It means that results about perception made with research prototypes are hard to generalize,and that using physical props is an alternative to evaluate best-case scenarios.
%\cite{bertin83}
\subsection{Vibrotactile widgets}
\label{sec:printgets}
-In the previous section we investigated the output vocabulary for a new device providing a new type of haptic feedback.
-We did not explore a particular context or application, but rather studied the possibilities and limitations of the technology.
-In this project we are interested in vibrotactile feedback, which is well covered in the literature.
+In the previous section, we investigated the output vocabulary for a new device providing a new type of haptic feedback.
+We did not explore a particular context or application but rather studied the possibilities and limitations of the technology.
+In this project, we are interested in vibrotactile feedback, which is well covered in the literature.
We are however interested in a particular case: restoring haptic feedback on touchscreens.
Indeed touchscreens have many advantages compares to physical interfaces.
They can be updated.
They have no mechanical parts that wear over time.
They are flat, so they are easy to clean.
However, physical interfaces such as buttons and sliders have interesting interactive properties.
-They have a relief that enable people to locate them with touch.
+They have a relief that enables people to locate them with touch.
They provide haptic feedback when they are operated: click sensation, detents, stops.
-These properties guarantee invaluable usability benefits, such as giving a continuous feedback of users actions and the discoverability of interactive elements.
+These properties guarantee invaluable usability benefits, such as giving continuous feedback of users' actions and the discoverability of interactive elements.
%Haptic properties of physical objects
The manufacturing process of touch interfaces such as dashboards augmented with haptic feedback is complex.
Mechanical actuators must be attached underneath such that the vibration transmits to the interactive places of the surfaces.
-In this project we investigate a new kind of actuators.
+In this project, we investigate a new kind of actuators.
%However, the originality of this work is that we used a new type of vibrotactile actuator.
They are printed on a flexible substrate with a piezo electric ink.
-Therefore, these actuators can be embedded in plastic injection molds when dashboard barts are produced.
-They can even be integrated in curved interactive surfaces.
+Therefore, these actuators can be embedded in plastic injection molds when dashboard parts are produced.
+They can even be integrated into curved interactive surfaces.
%This is convenient for dashboards with tactile input.
%Manufacturers are interested in this solution because it simplifies the fabrication process because they can include a flexible actuator sheet in their plastic injection molds.
-Our colleagues at CEA LITEN\footnote{\href{https://www.cea.fr/cea-tech/liten/english/Pages/Work-with-us/Technology-platforms/Large-Surface-Printed-Electronics.aspx}{Pictic platform}} designed and implemented the actuators and Walterpack\footnote{\href{http://www.walterpack.com/}{http://www.walterpack.com/}} worked on the integration of actuators in the plastic mold.
+Our colleagues at CEA LITEN\footnote{\href{https://www.cea.fr/cea-tech/liten/english/Pages/Work-with-us/Technology-platforms/Large-Surface-Printed-Electronics.aspx}{Pictic platform}} designed and implemented the actuators, and Walterpack\footnote{\href{http://www.walterpack.com/}{http://www.walterpack.com/}} worked on the integration of actuators in the plastic mold.
We prototyped the driving electronics and clamping system, designed tactile widgets, and implemented a dashboard prototype that was showcased at the Geneva Motor Show 2017\footnote{\href{https://www.carscoops.com/2017/03/this-is-what-sbarro-mojave-really-looks/}{Mojave} concept car, produced by the \href{http://www.e-sbarro.fr/}{Esperra Sbarro} school} (\reffig{fig:mojave}).
\begin{figure}[htb]
\subsubsection{Experimental platform}
\label{sec:printgetsplatform}
-The design of the actuators is a trade-off between their size and thickess, the number of layers and the signal voltage.
-Our colleagues who designed and implemented these actuators, performed FEM simulations, and measured the response to signal with laser vibrometers~\cite{poncet17,poncet16}.
+The design of the actuators is a trade-off between their size and thickess, the number of layers, and the signal voltage.
+Our colleagues whom designed and implemented these actuators performed FEM simulations and measured the response to signal with laser vibrometers~\cite{poncet17,poncet16}.
They gave us several prototypes that we could use to design vibrotactile widgets.
The first prototype (top of~\reffig{fig:printedslider}) had six buttons embedded in a molded plastic dashboard part.
The clamping area was a circle around each actuator.
We designed a clamping frame around the actuators so that the vibration could propagate on the whole length of the slider.
We added tension strings to tighten the frame so that the clamping area could resonate.
This is the same approach than a drum head on a drum shell.
-The capactitive touch sensor, printed with silver ink, is under the actuators.
+The capacitive touch sensor, printed with silver ink, is under the actuators.
The setup is depicted at the bottom of~\reffig{fig:printedslider}.
\begin{figure}[htb]
The idea of using vibrations to simulate button clicks on touch surfaces started with vibrotactile actuators attached to PDAs~\cite{fukumoto01,nashel03,poupyrev02}, then mobile phones~\cite{brewster07,hoggan08}.
This was before phone manufacturers included vibrotactile actuators to mobile phone.
-And even now mobile phones do have one, it is low quality (ERM or LRA) and mostly used for message or call notifications.
+And even now that mobile phones do have one, it is low quality (ERM or LRA) and mostly used for message or call notifications.
They sometimes propose vibrations for button presses, but the quality of this feedback is poor.
-Indeed other actuators provide a sharper vibrotactile feedback, we discussed this at the beginning of this chapter.
-Voice coil actuators provide precise and strong vibrations~\cite{yao10}, and piezo actuators have a smaller form factors, and convenient for implementing buttons~\cite{tashiro09,lylykangas11}.
+Indeed other actuators provide sharper vibrotactile feedback.
+We discussed this at the beginning of this chapter.
+Voice coil actuators provide precise and strong vibrations~\cite{yao10}, and piezo actuators have a smaller form factor, and are convenient for implementing buttons~\cite{tashiro09,lylykangas11}.
Our challenge is that printed actuators are thin (between $4\mu m$ and $10\mu m$).
Therefore the vibration propagation requires a careful design as discussed in the previous page.
%Neuromechanics button press ~\cite{oulasvirta18}
Kim and Lee analyzed force-displacement curves of physical buttons and designed high quality vibrotactile feedback that emulates button presses~\cite{kim13}.
They split force-displacement curves into two types of sections: slopes and jumps, which are delimited by tactile points (\reffig{fig:buttonfeedback}).
-Slopes are spring-like sensations that corresponds to the material resistance.
+Slopes are spring-like sensations that correspond to the material resistance.
When pressing a button we feel a first resistance before the click, then another one when the button reaches its end.
When releasing a button we feel another resistance before the click sensation.
The tactile points (1) and (3) represent the click sensations when the button physically switches, and the bottom-out (2) represents the end of the button.
We adapted and simplified these curves for the design and implementation of our buttons.
-We describe further our implementation of buttons, sliders and touchpads in~\cite{frisson20,frisson17}.
+We describe further our implementation of buttons, sliders, and touchpads in~\cite{frisson20,frisson17}.
\begin{figure}[htb]
\definecolor{cellred}{rgb} {0.98,0.17,0.15}
\subsubsection{Discussion and conclusion}
This work required interdisciplinary skills and knowledge to put together existing building blocks to design a whole system.
-This is what I consider a strength of Human-Cumputer Interaction research, at least the way I do it.
+This is what I consider a strength of Human-Computer Interaction research, at least the way I do it.
We have skills in many research domains, which allows us to design, implement and evaluate interactive systems.
When more expertise is required, we can efficiently collaborate with experts in other domains.
-In this project we collaborated with experts in material science who designed the tactile actuators modeled and simulated their vibrations in a theoretical environment.
+In this project, we collaborated with experts in material science who designed the tactile actuators, modeled and simulated their vibrations in a theoretical environment.
%Our colleagues who designed the tactile actuators modeled and simulated their vibrations in a theoretical environment.
In these simulations, there was no finger, and the clamping of the surface was perfect, without tension.
-In practice, the finger dampens the vibration and it is unsure other vibrations disrupt the perceptions of the vibrations produced by the device.
-In particular the main scenario of the project\footnote{\href{https://cordis.europa.eu/project/id/645145}{H2020 Happiness}, grant agreement \#645145} was a car dashboard.
+In practice, the finger dampens the vibration, and it is unsure other vibrations disrupt the perceptions of the vibrations produced by the device.
+In particular, the main scenario of the project\footnote{\href{https://cordis.europa.eu/project/id/645145}{H2020 Happiness}, grant agreement \#645145} was a car dashboard.
Cars produce vibrations of various frequencies and amplitudes because of the engine and the road.
Other partners of the project actually evaluated the perception of this tactile feedback in a real-case scenario~\cite{ng17}.
On our side, we noticed the clamping of research prototypes is not trivial.
It is difficult to glue the flexible substrate on a rigid surface with a clamping area so that the substrate remains perfectly flat on the clamping area.
-It creates a bi-stable condition on a surfaces that produces an undesirable click sensation when touching it with a finger.
+It creates a bi-stable condition on the surface that produces an undesirable click sensation when touching it with a finger.
Therefore we must apply tension to hold the flexible substrate flat on the rigid surface.
-It is well known that adjusting the tension of a drum head on a drum shell changes its resonnant frequency.
+It is well known that adjusting the tension of a drum head on a drum shell changes its resonant frequency.
This is precisely the way we tune a drum.
The same principle applies to our setup.
-However the vibration was still perceptible, with no bi-stable condition.
+However, the vibration was still perceptible, with no bi-stable condition.
A difficulty of this work was the long manufactoring process of actuators.
It required weeks of planning, and the actuators were printed in a white clean room.
-This long process limited the number of iterations we could perform for designing the actuator layout and properties such as thickness, shapes and sizes.
+This long process limited the number of iterations we could perform for designing the actuator layout and properties such as thickness, shapes ,and sizes.
Therefore at each iteration we printed several configurations, then tested them to select the most appropriate one.
-However it limited the type of user studies we could perform.
+However, it limited the type of user studies we could perform.
One of the major differences between this vibrotactile technology and other piezo-based actuators is that their thickness is very low.
-It is an advantage because it uses less materials.
+It is an advantage because it uses fewer materials.
It is also a drawback because the amplitude of vibration is much lower.
Therefore the vibration hardly transmits to thick surfaces like a 1mm thick plastic dashboard.
-The alternative is placing the actuators on holes that define a clamping area so that the substrate resonnates like a drum shell.
+The alternative is placing the actuators on holes that define a clamping area so that the substrate resonates like a drum shell.
This solution brings an interesting property that other technologies do not have.
-The vibration is localized to the clamping area, therefore it is localized.
+The vibration is localized to the clamping area therefore it is localized.
Hence with a dashboard with several buttons and sliders, it is possible to vibrate buttons individually.
% Leverage the physical properties of computer peripherals. Use them as tangibles~\cite{pietrzak17}.
% Actuated peripherals.
+The previous project addressed technological issues due to the replacement of physical interfaces by touch interfaces.
+In particular, we studied a hatpic technology that could restore the haptic feedback of physical controls.
+This project is the exact opposite.
+We embrace physical controls and study how we can better include them in our daily activities beyond the way they usually work.
+
+
+
+
+
+
+\newpage
+
In the early days of tangible interaction, Ullmer and Ishii described Tangible interaction this way: “TUIs will augment the real physical world by coupling digital information to everyday physical objects and environments.”\cite{ishii97}.
The idea is to break the barrier between the physical and the digital world.
With this paradigm, any object can either represent digital information or be a proxy for manipulating digital information.
projects / hdr.git / commitdiff